Traffic problems are poised to worsen as the population grows and more people gravitate toward cities. But a lot of people in both the public and private sectors are working to find solutions.

America’s roads are already packed with traffic, and all signs point to the number of cars growing even more — especially in cities. According to a report released last month, 60 percent of the world’s population will likely live in cities by 2030. And automotive analysts expect the demand for cars to grow as more and more people enter the middle class.

Despite this, there are many signs that government entities are working to reduce the need for private car ownership — or in some cases, to eliminate it entirely. But to do so will require a lot of puzzle pieces to fall into place.

Steven Swartz, a co-author of the report by consultancy firm McKinsey and Co., said the key is for governments to be flexible and encourage innovative solutions. There’s a cocktail of solutions to specific problems brewing, and nobody knows for sure which ones will work and which ones will be the most important or useful.

“My sense is that the folks who create the most robust environment for experimentation as you go through this kind of genesis that we’re going through [are] ultimately going to be the ones that figure this out,” he said.

Here are five technologies government can directly implement, participate in or encourage that offer promise for solving transit issues:

1. Leveraging the crowd

Crowdsourcing isn’t restricted to Bay Area tech startups — it’s found its way into the halls of government as well. Using open-ended smartphone apps, cities are looking at new ways to solve the same problems they’ve always faced, including traffic issues.

They may not be solutions to big-picture problems like traffic congestion and greenhouse gas emissions, but projects like Boston’s Street Bump app help cities take care of the little things that contribute to mobility problems. The app sits passively in users’ pockets as they navigate the roads, collecting information on the smoothness of the ride and delivering that data back to the city. The city can then analyze the inputs to find potholes and bumpy roads in need of repair for other reasons — essentially putting cars and cell phones to work as roaming sensors in the employ of the city.

Another city, Austin, Texas, is working to create an app that connects cyclists to traffic signals. The goal is to encourage more bicycling by making lights turn green faster as bicycles approach them.

Then there’s SeeClickFix, an app aimed at civic engagement. While SeeClickFix is a private-sector company, it works with municipalities to connect them to citizen-generated complaints. Using the app or website, people can post problems ranging from graffiti to street signs in disrepair. City 311 centers and other municipal employees can then browse the problems, take care of them and notify users of the solutions through the app.

Despite SeeClickFix's success, not all cities have enjoyed the app; some have complained that it creates an expectation among users that someone will solve any given issue. But in some cities, citizens were submitting problems while government officials never knew the app existed. Nonetheless, the app is growing after receiving $1.6 million in investment money this year.

Taken together, apps and other crowdsourced platforms are presenting to government an opportunity to identify problems more efficiently and engage citizens more directly.

“There is no aspect of travel that is not being transformed by [information technology],” wrote Tiffany Fishmann, author of a 2014 Deloitte report on urban mobility. “Route planning, finding one’s way while in the car or on foot, collecting fares or tolls, congestion and road pricing, traffic management, deciding among different transportation options for a given trip, reducing trips through telecommuting — all are evolving at dizzying speed.”

2. Vehicle-to-vehicle and vehicle-to-infrastructure connections

Cars are getting smarter — not just because they’re on the verge of being able to drive themselves or because they’re becoming more fuel efficient, but also because the U.S. is looking to turn them all into mobile data points.

The concepts of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) technology are well on their way to becoming a reality. The idea is to connect cars to each other via computers, allowing them to know where other cars are and augment driver decisions — or, if cars are driving themselves, make better-informed decisions. On top of that, some are hoping to connect vehicles to infrastructure like traffic lights to create better pictures of congestion and to let cars know ahead of time when a light will change.

The U.S. Department of Transportation sees potential benefits in V2V/V2I spanning the entire transportation system. In 2009, the department estimated that the technology could lead to interventions in one form or another in 80 percent of all accidents — for instance, preventing cars from running red lights, alerting them to when a car ahead is decelerating and communicating to a car making a left turn in front of another.

Two of the technologies alone, “left turn assist” and “intersection movement assist,” could prevent up to 592,000 crashes and 1,083 fatalities per year, the department estimated.

The technology also has the potential to help relieve traffic congestion insofar as it could easily offer the public a clear picture of what areas are congested. That’s the focus of a project in Tampa, Fla., where the city has received a $17 million grant from the DOT to launch a smartphone application delivering information on traffic flow.

The department has also awarded about $25 million in grants to New York City and Wyoming to pilot test V2V/V2I technology. In New York, the city will equip 10,000 of its vehicles, as well as traffic signals in midtown Manhattan, with sensors that can all communicate with each other as a network. In Wyoming, the state will study trucking along a corridor of Interstate 80 on which 11,000 to 18,000 vehicles per day travel.

And that’s just the beginning: The U.S. Department of Transportation has publicly declared that it intends to begin the process this year to implement a requirement that all new cars have V2V/V2I technology.

3. Car-free zones

Some cities close off streets to cars for a day to accommodate parades. Some keep them that way permanently.

According to the McKinsey report, major cities around the globe like Paris, London and New York have begun to create car-free zones in an effort to make it easier for pedestrians and cyclists to get around.

The concept has actually been around for a long time: According to the report, the city of Mdina in Malta has never allowed cars, and Buenos Aires has blocked off portions of the Calle Florida to traffic since 1913.

But more cities have been introducing car-free zones in recent years, and doing so has led to traffic improvements in cities like Copenhagen alongside programs that encourage bike riding.

4. Bike sharing programs

Congestion in the nation’s capital is nothing short of epic: According to the 2015 Urban Mobility Scorecard from Texas A&M University and INRIX, traffic gridlock in Washington, D.C., caused 82 hours of delay per auto commuter last year. Put another way, the average car driver spent almost three-and-a-half days stuck in traffic.

The public problems created by congestion have been well-documented. The scorecard conceptualized congestion as a type of tax that takes its collections in the form of missed meetings, delayed deliveries and fuel wasted while autos sit idling. Experts who are setting up sensor networks to map urban smog have noted that places where cars sit idling, such as intersections, are hotspots for poor air quality.

Enter bicycles, which can zip along the sides of idle cars and expel zero greenhouse gases. In 2008, Washington, D.C., launched the country’s first municipal bike-sharing program, where citizens pay a membership to get easy access to bike racks. Commuters can then ride those bikes to other racks and drop them off.

Since 2008, cities across the country have latched onto the concept. The Bay Area Bike Share offers more than 700 bicycles across 70 locations in California’s sprawling Bay Area. The contractor BCycle operates bike share programs in almost 30 cities.

Bike share operators have also sought to make the projects smarter, fitting the bikes with GPS trackers and monitoring which stations bikes are taken from, where they end up and how long it took them to get there. Many are opening up that data, anonymized, to the public — the average trip logged in the District of Columbia’s bike share database during the second quarter of 2015 was just shy of 20 minutes.

BCycle offers the data to individual users, who can access dashboards that tell them how many calories they’ve burned biking, estimates of their carbon offsets and how far they’ve cycled.

5. Multi-modal transit

All the above solutions — along with long-standing services offered by government entities like buses, carpool lanes and trains — present a mostly unexploited opportunity to create transit networks. Drawing from emerging technologies, the Deloitte and McKinsey reports describe a future in which a person uses technology to find the fastest, cheapest, most efficient way to get from point A to point B.

Many pieces of that puzzle are beginning to fall into place: Singapore offers an “ez-Link” program that allows customers to pay for buses, trains and some taxicabs with the same card. London’s Oyster card similarly integrates payment across various types of transit.

That’s important because it cuts down on the hassle factor that might otherwise make multi-modal transit less appealing, Swartz said.

“That is a huge advantage to driving — you get in, you drive and you get out of the car,” Swartz said. “So we do see multi-modal simplification as a huge [necessity] for … encouraging multi-modal transportation.”

Some projects are seeking to simplify trip planning in other ways. The Century City Transportation Management Organization in Los Angeles offers a commute planning dashboard where users can plot out possible routes comparing the cost, time and carbon emissions associated with using various means of transportation to get where they need to go. Users earn points for choosing low- or zero-carbon methods, and can then redeem those points for coupons to be used for public transit.

Perhaps the most ambitious project is in Helsinki, where McKinsey & Co. is reporting that the city and private sector are working together to create an app that adds payment to the mix. That is, it not only allows users to plot out a multi-modal commute, but also allows users to book and pay for any part of that commute they need to with one click. Swartz said Helsinki is also offering on-demand bus service.

The goal in Helsinki is to make private cars unnecessary by 2025.

Another problem that needs to be addressed is the issue of what Swartz calls the “first and last mile” — that is, the means by which pedestrians reach the first part of their multi-modal journey, and the way they get to their destination once they reach the other end.

There are several emerging concepts that could add to the options available for first and last mile transit. Bike sharing programs like the ones above are part of it, but there also are car-pooling apps that allow drivers and riders who share commutes to connect. There are apps for specific groups, like the Carpool-Kids App that’s geared toward parents whose children go to the same schools and activities, and then there are more general services like Carma and Hitch-A-Ride. Putting a spin on the concept, Getaround lets car owners rent out their vehicles while they would otherwise sit idle.

Then there are companies like Zipcar, which operate somewhat like bike share programs but with cars. Users buy memberships to the service and then have access to cars that are left in spots around the city; users drive to where they need to go and then leave the vehicle for the next user.

With so many different parties looking to edge into the market, and with so many opportunities for government to solve traffic problems, the McKinsey authors expect big changes in the nature of transportation.

“Urban mobility will likely be lower cost, faster and safer, and the lines between private and public transport will be increasingly blurred,” the authors wrote in the report.